A cosmos in motion<\/strong><\/h2>The key thing to remember here is that in space, nothing is ever still. You probably feel like you\u2019re sitting still as you read this, but you\u2019re not.<\/p>
Earth is spinning on its axis at a speed of around 1,600km (1,000 miles) per hour.<\/p>
It\u2019s also whizzing around the Sun at around 108,000 km\/h (67,000 mph), and beyond that, there\u2019s the Solar System\u2019s own velocity to take into account, as it circles the centre of the Milky Way<\/a> at a staggering 828,000 km\/h (500,000 mph).<\/p>And that\u2019s before we even consider the ongoing expansion of the Universe<\/a>\u2026<\/p>![\"Artist's](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/01\/earth-in-milky-way-1024x1024.jpg?fit=800%2C800\")
Artist’s impression showing where the Sun and Earth are located in the Milky Way. Credit: NASA<\/figcaption><\/figure>The cosmos is, in short, a bewildering melange of different forces whose combined effects mean that everything in it is constantly on the move, with some objects being drawn inexorably closer together while others creep ever further apart.<\/p>
It\u2019s all very confusing, but human beings are quite clever, so by the late 1970s, we had most of the above figured out \u2013 equations, formulas, esoteric constants and all.<\/p>
Except that then, someone noticed a problem.<\/p>![\"View](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/07\/norma-cluster-great-attractor-1024x992.jpg?fit=800%2C775\")
View of the sky in the Southern Hemisphere constellation of Norma, the direction of the Great Attractor. Credit: ESO<\/figcaption><\/figure>Discovering the Great Attractor<\/strong><\/h2>Astronomers studying the redshift<\/a> of other galaxies (the extent to which their light has been \u201cstretched\u201d out to longer wavelengths on its journey to Earth, which is a useful indicator of their distance) noticed that, on top of all the movement you\u2019d expect due to the phenomena outlined above, the Milky Way and other nearby galaxies seemed ALSO to be moving at around 600km\/s towards a point in space lying beyond the plane of the Milky Way, in the direction of the constellations Triangulum Australe, the Southern Triangle and Norma, the Carpenter\u2019s Square.<\/p>Unfortunately, lying beyond the Milky Way\u2019s galactic plane put this region in the \u2018Zone of Avoidance\u2019: that part of space where we can\u2019t see anything because it\u2019s blocked by the light of the Milky Way.<\/p>![\"Gaia's](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2019\/05\/Gaia_Milky_Way_Image_-ESAGaiaDPAC-CC-BY-SA-3.0-IGO-5e7ebb3.jpg\")
Gaia’s all-sky view of the Milky Way based on the measurements of almost 1.7 billion stars. Credit: ESA – ESA\/Gaia\/DPAC, CC BY-SA 3.0 IGO<\/figcaption><\/figure>So while the Great Attractor\u2019s effects were first observed in 1978, it wasn\u2019t until nearly a decade later, following advances in X-ray astronomy, that we were able to create more accurate \u2018map\u2019 of the Universe, and so work out what was going on.<\/p>
And it\u2019s back to lots of confusing motion again!<\/p>
The Milky Way and the other galaxies in our local group are being pulled towards a much larger group called the Virgo cluster, which in turn is drifting towards an even larger group called the Virgo supercluster<\/a>\u2026 which in turn is moving towards the centre of an even larger supercluster known as Laniakea.<\/p>And at the heart of Laniakea lies, you guessed it, the Great Attractor.<\/p>![\"A](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2022\/04\/Laniakea-supercluster-d05a767.png\")
A map of superclusters, with Laniakea indicated in yellow. Credit: Richard Powell \/ Wiki<\/figcaption><\/figure>So what is the Great Attractor?<\/strong><\/h2>The Great Attractor, in other words,\u00a0 is not so much a THING \u2013 like a star<\/a>, comet<\/a> or galaxy<\/a> \u2013 but a PLACE, the central gravitational point of the Laniakea supercluster. And that\u2019s where we\u2019re hurtling at a dizzying 600 km\/s.<\/p>\u00a0There\u2019s a catch, though: we\u2019ll never actually get there!<\/p>
Because it\u2019s so huge, the Laniakea isn\u2019t gravitationally bound, in the way that galaxies and galaxy groups<\/a> are.<\/p>
And that\u2019s before we even consider the ongoing expansion of the Universe<\/a>\u2026<\/p> The cosmos is, in short, a bewildering melange of different forces whose combined effects mean that everything in it is constantly on the move, with some objects being drawn inexorably closer together while others creep ever further apart.<\/p> It\u2019s all very confusing, but human beings are quite clever, so by the late 1970s, we had most of the above figured out \u2013 equations, formulas, esoteric constants and all.<\/p> Except that then, someone noticed a problem.<\/p> Astronomers studying the redshift<\/a> of other galaxies (the extent to which their light has been \u201cstretched\u201d out to longer wavelengths on its journey to Earth, which is a useful indicator of their distance) noticed that, on top of all the movement you\u2019d expect due to the phenomena outlined above, the Milky Way and other nearby galaxies seemed ALSO to be moving at around 600km\/s towards a point in space lying beyond the plane of the Milky Way, in the direction of the constellations Triangulum Australe, the Southern Triangle and Norma, the Carpenter\u2019s Square.<\/p> Unfortunately, lying beyond the Milky Way\u2019s galactic plane put this region in the \u2018Zone of Avoidance\u2019: that part of space where we can\u2019t see anything because it\u2019s blocked by the light of the Milky Way.<\/p> So while the Great Attractor\u2019s effects were first observed in 1978, it wasn\u2019t until nearly a decade later, following advances in X-ray astronomy, that we were able to create more accurate \u2018map\u2019 of the Universe, and so work out what was going on.<\/p> And it\u2019s back to lots of confusing motion again!<\/p> The Milky Way and the other galaxies in our local group are being pulled towards a much larger group called the Virgo cluster, which in turn is drifting towards an even larger group called the Virgo supercluster<\/a>\u2026 which in turn is moving towards the centre of an even larger supercluster known as Laniakea.<\/p> And at the heart of Laniakea lies, you guessed it, the Great Attractor.<\/p> The Great Attractor, in other words,\u00a0 is not so much a THING \u2013 like a star<\/a>, comet<\/a> or galaxy<\/a> \u2013 but a PLACE, the central gravitational point of the Laniakea supercluster. And that\u2019s where we\u2019re hurtling at a dizzying 600 km\/s.<\/p> \u00a0There\u2019s a catch, though: we\u2019ll never actually get there!<\/p> Because it\u2019s so huge, the Laniakea isn\u2019t gravitationally bound, in the way that galaxies and galaxy groups<\/a> are.<\/p>Discovering the Great Attractor<\/strong><\/h2>
So what is the Great Attractor?<\/strong><\/h2>